Abstract:

Pyrolysis Spirulina platensis residue (SPR) processing/produces tar, char, and gas products. Tar upgrading with a catalyst is carried out to reduce the oxygenate content in the tar. The reaction kinetics of oxygenate compounds in tar to form aliphatic, aromatic, oxygenate, and coke and gas compounds must be calculated. The calculation determines the reaction rate constant (k) and activation energy (E) value. This paper discusses the catalytic kinetic components of ex-situ slow pyrolysis of Spirulina platensis residue with silica-alumina via a 5-lump model. Values of k and E can predict the predominance of product compound formation tendencies and are required for industrial design. A fixed-bed reactor with a silica-alumina catalyst operates with a temperature range of 300–600 °C, the thickness of the catalyst in the reactor R2 is 0–4.5 cm, and the heating rate is 5–35°C/min. The reactor consists of two (2) vertical cylinders, reactor R1 contains the SPR, and reactor R2 is filled with the catalyst. Based on experimental data, the decomposition of oxygenating products into aliphatic products is more dominant than the decomposition of aliphatic and aromatic compounds into other products. The dominance of aliphatic formation is indicated by the lowest activation energy value (0.07 kJ/mol) occurring in the k6 reaction (11.779-11.835 sec.-1), i.e., the oxygenate product becomes aliphatic. The lowest E value indicates oxygenate compounds are more easily decomposed than aromatic and aliphatic compounds. The product oxygenates, aliphatic, aromatic, coke, and gas compounds increased with increasing catalyst thickness; on the other hand, the pyrolysis feed oxygenate compound decreased sharply.<

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